The BMW Z4 (E89) 35i sDrive Steptronic, produced from 2009 to 2013, represented a significant step forward for BMW’s two-seater roadster. This generation Z4 moved away from the folding hardtop of its predecessor (E85) and embraced a more traditional soft-top convertible design, aiming for a blend of sporty handling and open-air driving enjoyment. The 35i variant, equipped with the N54B30A inline-six engine and a six-speed automatic transmission (later upgraded to an eight-speed), occupied the performance-oriented mid-to-upper range of the E89 Z4 lineup, positioned above the 28i and 23i models. It was marketed towards drivers seeking a more engaging and powerful driving experience than the base models offered, but without the ultimate performance focus of potential future M variants.
Technical Specifications
| Brand | BMW |
| Model | Z4 |
| Generation | Z4 (E89) |
| Type (Engine) | 35i (306 Hp) sDrive Steptronic |
| Start of production | 2009 |
| End of production | 2013 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Roadster |
| Seats | 2 |
| Doors | 2 |
| Fuel consumption (urban) | 12.6 l/100 km (18.7 US mpg) |
| Fuel consumption (extra urban) | 6.9 l/100 km (34.1 US mpg) |
| Fuel consumption (combined) | 9 l/100 km (26.1 US mpg) |
| CO2 emissions | 210 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 5.1 sec |
| Acceleration 0 – 62 mph | 5.1 sec |
| Acceleration 0 – 60 mph | 4.8 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Weight-to-power ratio | 5.2 kg/Hp |
| Weight-to-torque ratio | 4 kg/Nm |
| Power | 306 Hp @ 5800 rpm |
| Torque | 400 Nm @ 1300-5000 rpm (295.02 lb.-ft. @ 1300-5000 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | N54B30A |
| Engine displacement | 2979 cm3 (181.79 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 84 mm (3.31 in.) |
| Piston Stroke | 89.6 mm (3.53 in.) |
| Compression ratio | 10.2:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Twin-power turbo, Intercooler |
| Engine oil capacity | 6.5 l (6.87 US qt | 5.72 UK qt) |
| Coolant capacity | 8.5 l (8.98 US qt | 7.48 UK qt) |
| Kerb Weight | 1600 kg (3527.4 lbs.) |
| Max. weight | 1855 kg (4089.57 lbs.) |
| Max load | 255 kg (562.18 lbs.) |
| Fuel tank capacity | 55 l (14.53 US gal | 12.1 UK gal) |
| Length | 4239 mm (166.89 in.) |
| Width | 1790 mm (70.47 in.) |
| Height | 1291 mm (50.83 in.) |
| Wheelbase | 2496 mm (98.27 in.) |
| Front track | 1511 mm (59.49 in.) |
| Rear track | 1559 mm (61.38 in.) |
| Drive wheel | Rear wheel drive |
| Number of gears | 6/8 (depending on year) |
| Gearbox type | Automatic transmission |
Powertrain & Engine Architecture
The heart of the Z4 35i is the N54B30A 3.0-liter inline-six engine. This engine is a marvel of engineering, featuring direct fuel injection, a twin-turbocharger setup, and variable valve timing (VANOS) on both the intake and exhaust camshafts. The twin-turbo configuration, utilizing smaller turbochargers, minimized turbo lag and provided a broad, flat torque curve. The N54 was known for its responsiveness and ability to be readily tuned for increased performance. Initially paired with a six-speed automatic transmission, BMW later offered an eight-speed automatic, improving fuel efficiency and providing smoother shifts. The transmission featured Sport and manual shift modes, allowing drivers to exert more control over gear selection. The engine’s longitudinal mounting and rear-wheel drive configuration contributed to the car’s balanced handling characteristics.
Driving Characteristics
The Z4 35i sDrive Steptronic delivered a compelling driving experience. The 306 horsepower and 400 Nm (295 lb-ft) of torque provided brisk acceleration, with 0-60 mph times consistently in the high 4-second range. The automatic transmission, while not as engaging as a manual, offered smooth and relatively quick shifts, especially in the sportier settings. Compared to the 28i and 23i models, the 35i offered a significantly more potent power delivery, making it more enjoyable for spirited driving. While the manual transmission offered in other Z4 variants provided a more direct connection to the engine, the automatic’s ease of use made it a popular choice for daily driving. The car’s relatively low weight and well-tuned suspension contributed to its agile handling and cornering ability.
Equipment & Trim Levels
The Z4 35i typically came well-equipped, though options were plentiful. Standard features included leather upholstery, power-adjustable seats, automatic climate control, a premium sound system, and BMW’s iDrive infotainment system. Optional extras included navigation, heated seats, park distance control, and a retractable hardtop (though the E89 was primarily a soft-top model). Interior trim options ranged from basic cloth to more luxurious leather packages. Exterior options included various wheel designs, paint colors, and aerodynamic enhancements. The overall interior design was driver-focused, with a clean and functional layout.
Chassis & Braking
The Z4 E89 utilized a MacPherson strut front suspension and a multi-link rear suspension, providing a good balance of comfort and handling. The 35i model typically featured slightly stiffer springs and dampers compared to the lower-powered variants to better manage the increased power. Braking duties were handled by ventilated disc brakes on all four wheels, with ABS and dynamic stability control (DSC) as standard features. The DSC system helped to maintain stability during cornering and emergency maneuvers. The car’s relatively lightweight construction contributed to its responsive braking performance.
Market Reception & Comparison
The Z4 35i was generally well-received by automotive critics. It was praised for its powerful engine, engaging handling, and comfortable interior. However, some reviewers noted that the automatic transmission, while competent, lacked the involvement of a manual gearbox. Compared to rivals like the Porsche Boxster and Mercedes-Benz SLK, the Z4 35i offered a compelling value proposition, providing similar performance and features at a lower price point. Fuel economy was reasonable for a performance roadster, averaging around 26 mpg in combined driving. Reliability was generally good, although the N54 engine was known to require careful maintenance, particularly regarding the cooling system and fuel injectors.
Legacy
The Z4 E89 35i remains a desirable used sports car today. The N54 engine, while requiring diligent maintenance, is capable of delivering years of reliable performance when properly cared for. The car’s combination of power, handling, and open-air driving enjoyment continues to appeal to enthusiasts. The E89 generation Z4, and particularly the 35i variant, represents a sweet spot in BMW’s roadster lineage, offering a blend of modern technology and classic sports car characteristics. Values have remained relatively stable, making it an accessible entry point into the BMW performance roadster world.
